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<a name="MeP-Pragmas"></a>
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<hr>
<a name="MeP-Pragmas-1"></a>
<h4 class="subsection">6.61.4 MeP Pragmas</h4>

<dl compact="compact">
<dt><code>custom io_volatile (on|off)</code></dt>
<dd><a name="index-pragma_002c-custom-io_005fvolatile"></a>
<p>Overrides the command-line option <code>-mio-volatile</code> for the current
file.  Note that for compatibility with future GCC releases, this
option should only be used once before any <code>io</code> variables in each
file.
</p>
</dd>
<dt><code>GCC coprocessor available <var>registers</var></code></dt>
<dd><a name="index-pragma_002c-coprocessor-available"></a>
<p>Specifies which coprocessor registers are available to the register
allocator.  <var>registers</var> may be a single register, register range
separated by ellipses, or comma-separated list of those.  Example:
</p>
<div class="smallexample">
<pre class="smallexample">#pragma GCC coprocessor available $c0...$c10, $c28
</pre></div>

</dd>
<dt><code>GCC coprocessor call_saved <var>registers</var></code></dt>
<dd><a name="index-pragma_002c-coprocessor-call_005fsaved"></a>
<p>Specifies which coprocessor registers are to be saved and restored by
any function using them.  <var>registers</var> may be a single register,
register range separated by ellipses, or comma-separated list of
those.  Example:
</p>
<div class="smallexample">
<pre class="smallexample">#pragma GCC coprocessor call_saved $c4...$c6, $c31
</pre></div>

</dd>
<dt><code>GCC coprocessor subclass '(A|B|C|D)' = <var>registers</var></code></dt>
<dd><a name="index-pragma_002c-coprocessor-subclass"></a>
<p>Creates and defines a register class.  These register classes can be
used by inline <code>asm</code> constructs.  <var>registers</var> may be a single
register, register range separated by ellipses, or comma-separated
list of those.  Example:
</p>
<div class="smallexample">
<pre class="smallexample">#pragma GCC coprocessor subclass 'B' = $c2, $c4, $c6

asm (&quot;cpfoo %0&quot; : &quot;=B&quot; (x));
</pre></div>

</dd>
<dt><code>GCC disinterrupt <var>name</var> , <var>name</var> &hellip;</code></dt>
<dd><a name="index-pragma_002c-disinterrupt"></a>
<p>For the named functions, the compiler adds code to disable interrupts
for the duration of those functions.  If any functions so named 
are not encountered in the source, a warning is emitted that the pragma is
not used.  Examples:
</p>
<div class="smallexample">
<pre class="smallexample">#pragma disinterrupt foo
#pragma disinterrupt bar, grill
int foo () { &hellip; }
</pre></div>

</dd>
<dt><code>GCC call <var>name</var> , <var>name</var> &hellip;</code></dt>
<dd><a name="index-pragma_002c-call"></a>
<p>For the named functions, the compiler always uses a register-indirect
call model when calling the named functions.  Examples:
</p>
<div class="smallexample">
<pre class="smallexample">extern int foo ();
#pragma call foo
</pre></div>

</dd>
</dl>

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